Material handlers of the type contemplated by the present invention are usually extremely large and complex, requiring significant investments in time, material and engineering. Such apparatus are normally associated with shiploaders, and particularly known as linear shiploaders or linear loaders. Such an apparatus is described in U.S. Pat. No. 3,856,159 issued to the inventor Dec. 24, 1974, the contents of which are incorporated herein by reference. The linear shiploader has become very popular and is used in a number of rather massive shiploading installations throughout the world today. Heretofore, all of the linear loaders incorporated a front pivot movably mounted on rails extending transversely of the bridge and substantially parallel to the vessel being loaded and a fixed rear pivot support which included means for permitting longitudinal movement of the bridge relative to said fixed pivot support. Such a construction however, involved alternation in the direction of deflection under load of the rear part of the bridge, requiring special design attention. An alternative embodiment of the linear loader has been suggested in the aforementioned patent whereby the rear pivot support is not fixed but is mounted on rails extending perpendicularly to the front end rails. However, as described in the aforementioned patent, such an embodiment creates particular difficulties in continuously feeding a conveyor mounted on the slewing bridge since there is no fixed pivot point at which to feed the conveyor mounted on the bridge. For this reason all existing installations, representing an installed base valued at several hundred million dollars, utilize stationary feeding and a fixed rear pivot support. An overview of these existing installations and the design criteria pertinent to each installation is described in an article by the inventor published in Bulk Solids Handling magazine, Vol. 11, No. 1, dated Mar., 1991.
The present invention is directed to solving the feeding problem for a linear loader having the alternate structure described above, namely a movable rear pivot support.